Question: 
Write a python function to find the difference between sum of cubes of first n natural numbers and the sum of first n natural numbers.


Model's Code:
def difference(n):
    sum_n = n * (n + 1) // 2
    sum_cubes = sum_n ** 2
    return sum_cubes - sum_n



Sample Correct Code:
def difference(n) :  
    S = (n*(n + 1))//2;  
    res = S*(S-1);  
    return res;  


Asserts:
assert difference(3) == 30
assert difference(5) == 210
assert difference(2) == 6


Tests:
Test 1 of 3: PASS
Test 2 of 3: PASS
Test 3 of 3: PASS

Test 555 of 974: 410/555 (73.87387387387388%): success